The hallux valgus deformity (fibular deviation of the big toe) is one of the most common deformities affecting lower limbs. If the hallux crosses over the second toe, the condition may be termed hallux valgus superductus, if it moves under the second toe, the term hallux valgus subductus applies. Mechanical pressure on the pseudoexostosis results in a bunion and possibly fistulization. Hallux valgus is often combined with a splay foot. Overloading of the second to fourth metatarsal heads may cause midfoot pain. As a result of the increased load, the second to fifth toes may deform into hammer or claw toes. Therefore hallux valgus should usually not be considered in its own. Apart from the anamnesis and clinical examination, X-ray diagnosis is very important for the treatment planning. A.p. and lateral X-rays should be obtained of the entire foot in the standing patient, as also an oblique view. While the latter permits evaluation of the extent of an arthrosis of the metatarsophalangeal joint of the big toe, the lateral films allow the longitudinal arch and the stability of the first tarsometatarsal articulation to be assessed. On the a.p. film the hallux valgus angle and the intermetatarsal (rays 1/2) angle can be determined.